Subclinical Optic Nerve Changes After Le Fort I Osteotomy
Optic Nerve Diseases
What this study involves
The registry does not currently label this study as recruiting. Ask about its status before planning a screening visit.
- Study type
- Observational
- Phase
- Not applicable / not listed
- Age range
- 18 years - 45 years
- Sex eligible
- All sexes
- Healthy volunteers
- Accepted
- Participants
- 50 Estimated
These are starting points, not an eligibility decision. The research team must review the full requirements.
About the research
Le Fort I osteotomy is a common jaw surgery that includes a step called pterygomaxillary dysjunction, during which force applied with a surgical instrument (osteotome) can be transmitted toward the eye socket (orbit) and the optic nerve canal. Serious eye complications after this surgery are rare, but it is not known whether smaller, subclinical changes occur in the optic nerve that go unnoticed without special testing. This study uses a non-invasive eye imaging test called optical coherence tomography (OCT) to measure the thickness of the nerve fiber layer around the optic nerve, before and after Le Fort I surgery, to find out whether such changes occur.
Read the full description
Fifty patients aged 18-45 years scheduled for isolated Le Fort I osteotomy or Le Fort I osteotomy combined with bilateral sagittal split osteotomy (BSSO) will be enrolled in this single-center, prospective, observational cohort study. Each patient serves as their own control (within-subject comparison across time points). All participants will undergo ophthalmologic examination, RNFL-OCT imaging, optic disc morphology assessment (disc area, elongation ratio, presence of disc head hemorrhage), and Humphrey 30-2 visual field testing at three time points: preoperatively (T0, within 1 week before surgery), 1 week postoperatively (T1), and 3 months postoperatively (T2). All ophthalmologic measurements will be performed by a single examiner blinded to intraoperative surgical details, using the same device throughout. Maxillary advancement amount and pterygomaxillary junction depth/concavity angle will be measured preoperatively on CBCT (pterygomaxillary junction measured bilaterally, with Observer 1 measuring twice for intraobserver reliability and Observer 2 measuring once for interobserver reliability). No intervention, randomization, or treatment-group allocation occurs as part of this study; all participants receive their routine, already-planned orthognathic surgical care. A priori power analysis (G\*Power, RM ANOVA within-between interaction, f=0.25, epsilon=1, alpha=0.05, power=0.90) indicated a minimum required sample size of N=36; n=50 was set to allow for attrition.
Who may be able to participate?
The list below is the sponsor’s full registry wording. It can include conditions, prior treatment, test results and other requirements. A match in search does not mean you qualify.
Inclusion Criteria:
- Aged 18-45 years, able to provide written informed consent
- Isolated Le Fort I osteotomy or Le Fort I + BSSO (bilateral sagittal split osteotomy) planned
- ASA Physical Status Classification I-II
- Standard osteotome technique used for pterygomaxillary dysjunction
- Sufficient ocular media clarity to permit OCT imaging
Exclusion Criteria:
- Known glaucoma, optic neuropathy, retinal disease, or other ocular pathology affecting the retinal nerve fiber layer
- Prior ocular/orbital surgery or trauma
- Craniofacial syndrome (e.g., cleft lip/palate)
- Segmental Le Fort osteotomy or revision orthognathic surgery
- Unwilling or unable to provide informed consent
Study population
Adult patients aged 18-45 years scheduled for isolated Le Fort I osteotomy or Le Fort I combined with bilateral sagittal split osteotomy (BSSO) at Istanbul Medipol University, with no pre-existing ocular or orbital pathology that could independently affect retinal nerve fiber layer thickness or optic disc morphology.'
Understand screeningTreatment, groups and participation
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- Assignment
- Not reported
- Masking
- Not reported
Le Fort I osteotomy cohort
Patients undergoing isolated Le Fort I osteotomy or Le Fort I combined with bilateral sagittal split osteotomy (BSSO). No randomization or treatment allocation; all participants receive their routine, already-planned orthognathic surgical care. Diagnostic Test: RNFL-OCT and optic disc morphology assessment (disc area, elongation ratio, disc head hemorrhage), performed preoperatively (T0) and at 1 week (T1) and 3 months (T2) postoperatively. Diagnostic Test: Humphrey 30-2 visual field testing, performed at the same three time points. Diagnostic Test: Preoperative CBCT measurement of pterygomaxillary junction depth and concavity angle, and maxillary advancement amount from surgical planning data.
Diagnostic Test: RNFL-OCT and Optic Disc Assessment · Diagnostic Test: Diagnostic Test · Diagnostic Test: Preoperative CBCT Measurement of Pterygomaxillary Junction
RNFL-OCT and Optic Disc Assessment DIAGNOSTIC_TEST
Peripapillary retinal nerve fiber layer thickness and optic disc morphology (disc area, elongation ratio, presence of disc head hemorrhage) measured by optical coherence tomography, performed preoperatively (T0) and at 1 week (T1) and 3 months (T2) postoperatively.
Diagnostic Test DIAGNOSTIC_TEST
Humphrey 30-2 Visual Field Testing Açıklama: Standard automated perimetry (Humphrey 30-2 program) performed at the same three time points (T0, T1, T2) to assess mean deviation and pattern standard deviation.
Preoperative CBCT Measurement of Pterygomaxillary Junction DIAGNOSTIC_TEST
Cone-beam computed tomography measurement of pterygomaxillary junction depth and concavity angle, and maxillary advancement amount from virtual surgical planning data, obtained preoperatively.
What researchers are measuring
Outcome measures describe what is being studied. They are not proof that a treatment works.
Primary measures
Change in Peripapillary Retinal Nerve Fiber Layer (RNFL) Thickness
Time frame: Baseline (T0, preoperative) to 3 months (T2) postoperatively
Change in peripapillary retinal nerve fiber layer (RNFL) thickness, measured by optical coherence tomography (OCT), from baseline (T0, preoperative) to 1 week (T1) and 3 months (T2) after Le Fort I osteotomy.
Secondary measures
Change in Optic Disc Area and Elongation Ratio
Time frame: Baseline (T0) to 3 months (T2) postoperatively
Change in optic disc area and elongation ratio (vertical/horizontal), measured by OCT, from baseline (T0) to 1 week (T1) and 3 months (T2) after Le Fort I osteotomy.
Review the complete result tables and limitations in the official record.
Open official results ↗Research locations (0)
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No locations are listed. Use the official study contact.
Study team and timeline
- Lead sponsor
- Yağmur Malkoc
- Study start
- Nov 4, 2026 Estimated
- Primary completion
- Apr 4, 2028 Estimated
- Study completion
- Jul 4, 2028 Estimated
- First posted
- Nov 9, 2026 Actual
- Last updated
- Nov 10, 2026 Actual
Official study contacts
Official study title
Evaluation of Subclinical Optic Nerve Head Changes After Le Fort I Osteotomy Using Retinal Nerve Fiber Layer Optical Coherence Tomography
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Source: ClinicalTrials.gov API v2. Information is submitted by sponsors and investigators. NLM does not approve the safety or science of all listed studies. Registry disclaimer.
Retrieved: Nov 12, 2026 · Last registry update: Nov 10, 2026